code: def __len__(self):
      return len(self.history)
  
file_path: opacus/opacus/accountants/gdp.py
imports: import warnings
  from .accountant import IAccountant
  from .analysis import gdp
label_desc: Use image node_id 4 for calling the GaussianAccountant obj's underlying member method code with example usage: obj.__len__() and returns: len